Pinar Yolum Munindar P. Singh Reasoning about Commitments in the Event Calculus: An Approach for Specifying and Executing Protocols. 227-253 2004 42 Ann. Math. Artif. Intell. 1-3 http://www.springerlink.com/index/10.1023/B:AMAI.0000034528.55456.d9 db/journals/amai/amai42.html#YolumS04